OXYGEN TRACER DIFFUSION IN SINGLE-CRYSTAL ALUMINA

Oxygen tracer diffusion coefficients are determined in single-crystal alumina samples with differing dopant levels using the gas-exchange technique. The diffusion direction is parallel to the c-axis and the ambient P(o2) is 1 atm (10(5) Pa) for all experiments except a single run with a low P(o2) almost-equal-to 10(-15) atm (10(-10) Pa) produced by a CO/CO2 mixture. The diffusion is insensitive to both impurities and ambient P(o2). The insensitivities are discussed in terms of point-defect clustering. Prior tracer studies are compared and discussed.